[v3,0/2] huge_pmd_unshare migration and flushing

Message

Mike Kravetz Aug. 21, 2018, 8:59 p.m. UTC

v3 of a patch to correct a data corruption issue caused by improper
handling of shared huge PMDs during page migration.  This issue was
observed in a customer environment and can be recreated fairly easily
with a test program.  Patch 0001 addresses this issue only and is
copied to stable with the intention that this will go to stable
releases.  It has existed since the addition of shared huge PMD support.

While considering the issue above, Kirill Shutemov noticed that other
callers of huge_pmd_unshare have potential issues with cache and TLB
flushing.  A separate patch (0002) takes advantage of the new routine
huge_pmd_sharing_possible() to adjust flushing ranges in the cases
where huge PMD sharing is possible.  There is no copy to stable for this
patch as it has not been reported as an issue and discovered only via
code inspection.

Mike Kravetz (2):
  mm: migration: fix migration of huge PMD shared pages
  hugetlb: take PMD sharing into account when flushing tlb/caches

 include/linux/hugetlb.h | 14 +++++++
 mm/hugetlb.c            | 93 +++++++++++++++++++++++++++++++++++++----
 mm/rmap.c               | 42 +++++++++++++++++--
 3 files changed, 137 insertions(+), 12 deletions(-)